By Jason Deign in Barcelona

If you want to see the future of wind energy in Western Europe you will need a boat. As the amount of land freely available for wind farm use dwindles, developers are looking to new horizons… or, specifically, over the horizon at sites located tens of kilometres from the coast.

This summer saw Catalan Institut de Recerca en Energia de Catalunya (IREC, the Catalonia Institute for Energy Research) launching the Mediterranean’s first test platform for deepwater offshore wind energy equipment.

Called Zèfir, the test station will involve 12 wind turbine sites that will be hired out to developers for research. Four of the sites will be at just 3.5 km from the coast and will be used for turbine designs anchored to the seabed at a depth 35m.

The other eight, 30 km from the coast and at a depth of 100m, will be for floating wind turbines. “What we are trying to do is help the industry by providing pre-approved sites where developers can try different types of solutions,” says Antoni Martínez, IREC’s director general.

The Institute is talking to the Spanish maritime authorities about possible sites between the Cape of Salou, just south of Tarragona, and the Ebro delta, at the southern limit of Catalunya.

“There are places where this type of park is not compatible with marine use, but in the end it is only a relative problem,” Martínez says. “The sea is very big.”

Visual impact

And that is the big attraction. Spain’s landscape is already littered with wind farms and given that the country relies so heavily on tourism there is little room for further developments. “In Spain the visual impact is a very important factor,” Martínez points out.

Other European countries, such as Portugal, France or Ireland, may have similar concerns about wind farm development in areas where the landscape attracts tourist euros.

And elsewhere there is a different conflict: densely populated nations such as Germany, Holland or the United Kingdom may simply not have that much spare land that is suitable for wind farms.  

For this reason, and the fact that winds tend to be stronger and steadier at sea, interest in offshore developments is ramping up right across Western Europe. But there are considerable challenges to be overcome.

“The most important point is cost,” says Martínez. “We need to make this type of devices competitive.”

Currently they are anything but. In parts of the North Sea, the seabed drops away gently enough to have turbines anchored in 25 to 30m of water at up to 70km from the coast, so the type of wind turbines that can be used are essentially still the same as those on land.

Floating anchorages

But in most places elsewhere, including the Mediterranean, the seabed drops away steeply, so deepwater or, more likely, floating anchorages are needed. How best to build this kind of farms has yet to be fully worked out… but should be soon.

The energy company Statoil has already developed a full-scale floating wind turbine called Hywind that operates 10km off the southwest coast of Norway.

And about 600km south is Germany’s first offshore wind farm, alpha ventus, which went into operation in early 2009 with REpower and Siemens turbines and has so far delivered more than 110 gigawatt-hours to the German power grid.

“The main experience we gained is it took more time and was more expensive than we expected,” says Nina Hildebrandt, press relations officer for the project.

Much of this cost and expense has been down to logistical challenges. Components had to be shipped from the Netherlands and the wind farm’s distance from shore means maintenance crews can only work reduced shifts because of the time needed for travel.

While the REpower turbines have so far worked without a hitch, AREVA is overhauling its Multibrid models because of a manufacturing glitch with the gearboxes.

Marine turbines

Gearboxes have also been a problem for Siemens, says says Emerging Energy Research Europe Wind Energy Advisory research director Eduard Sala de Vedruna.

And the fact that besides these three manufacturers there is only one other, Vestas, currently offering marine turbines shows “this is a sector which is still very much at the prototype stage.”

A fifth company, BARD, produces its own turbines and recently sold its first commercial offshore wind farm, also in the German North Sea, to the utility SuedWestStrom Windpark GmbH.

However, in the next couple of years a slew of other turbine makers are set to enter the market. And the experience from test beds such as Zèfir and alpha ventus should help rapidly overcome today’s technical challenges.

“It’s more a matter of cost than technology,” Sala de Vedruna believes. “Being realistic, we’re talking about 2015 before this takes off… I don’t think it’s feasible to talk about anything shorter-term.” But take off it surely will.

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Image Credit: Vestas